Many automotive passenger vehicles come equipped with a driver's seat belt monitoring system that determines whether the driver's seat belt is latched or unlatched each time the vehicle ignition is turned on. Where the system determines that the driver's belt is not latched, an audible and/or visual reminder warning is provided to alert the driver of this condition. These systems can be provided for other occupant seats within the vehicle, although this is not currently done on a widespread basis. Rather, where a driver wishes to determine whether the seat belt of another occupant seat is latched or unlatched, the more typical method is either visual inspection, usually from the driver's seat, or querying of an occupant. Visual inspection from the driver's seat can be difficult, and querying children as to the status of their seat belt can be unreliable.
The monitoring systems commonly used today are electronically-implemented systems that may include circuitry at the driver's seat belt buckle which is hardwired to an operator signaling device at the instrument panel to produce the audible and/or visual warning. Using a hardwired system for other occupant seats can be problematic, especially when used on vans and the like that include removable seats. Independent status monitoring systems that do not require wiring between the instrument panel and seat have been proposed as well, and at least some of these systems use a battery-powered circuit to produce an audible alert at the seat belt buckle itself.